1. Field of the Invention
The present invention relates to systems and methods for performing parallel pipelining functions in a blood analyzing instrument. More specifically, the present invention relates to a pipelining assembly for a blood analyzing instrument.
2. Background
In diagnosing different illnesses and disease states, it is common to analyze a patient's peripheral blood to differentiate and enumerate the various constituents within the blood, as well as to determine certain parameters or characteristics of those constituents. Various measurement techniques, alone or in combination, have been implemented in blood analyzing instruments to differentiate and enumerate the various constituents in a whole blood sample (WBS). Blood tests can include, for example, a Nucleated Red Blood Cell (NRBC) test, Differential test, or a Reticulocyte test. For example, U.S. Pat. No. 6,228,652 (“the '652 patent”) discloses one such blood analyzing instrument. The blood analyzing instrument of the '652 patent includes a transducer for simultaneously measuring DC impedance, RF conductivity, light scattering, and fluorescence characteristics of a prepared blood sample passing through an analysis chamber, such as a flow cell. Additional systems are described in U.S. Pat. Nos. 5,125,737; 5,616,501; 6,232,125; 7,008,792; and 7,208,319.
Typical blood analyzing instruments distribute prepared samples using a mechanically driven multi-port distribution valve. Multi-port distribution valves have a common output port and two or more input ports. Multi-port distribution valves typically consist of two ceramic discs that are precisely machined to define port connections. One of the ceramic discs is held in place while the other disc is rotated using a stepper motor to align the output port to the user defined input ports. Input and output ports must be precisely aligned to ensure proper sample flow. Sensors must be used to keep track of disc rotation to ensure port alignment. Port misalignment can generate a series of system issues, including carryover, tubing pop-off due to pressure buildup, blood cell damage, and inconsistent and/or inefficient timing. Another disadvantage of multi-port distribution valves is that they typically require an analysis cycle to be processed through to completion before the system can be cleaned. In other words, the processes of analysis and cleaning must be performed in series.
Improving an instrument's throughput and efficiency is an important clinical objective. Presented herein is a pipelining assembly for performing parallel pipelining functions and avoiding the limitations of multi-port distribution valves.